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There’s a lot of noise online about semaglutide, sudden vision loss, and scary eye complications. If you’re taking a GLP-1 (or thinking about it), you might be wondering:

Am I putting my vision at risk?

In a recent conversation with Dr. Mina Farahani, a cornea, cataract, and refractive specialist at Spindel Eye Associates, we unpacked what the latest data actually says about GLP-1 medications and eye health.

Read on for a clear, evidence-based breakdown of the real risks, who needs closer monitoring, what symptoms you should never ignore, and the simple steps that protect your vision long term.

Are GLP-1 Medications Bad for Your Eyes? 

If GLP-1 medications help get your blood sugar under control, they're almost certainly going to be better for your eyes in the long run—not worse. Uncontrolled diabetes and metabolic syndrome are among the worst things for eye health. Anything that meaningfully lowers your A1C and improves cardiovascular risk factors is a win from an eye health perspective.

That said, there are a few things worth knowing, especially if you have diabetes or certain risk factors.

What Is NAION and Should You Be Worried?

The scary headline making the rounds involves a condition called non-arteritic ischemic optic neuropathy, or NAION. It's a bit of a mouthful, but here's what it means: the blood supply to the optic nerve gets cut off, causing painless vision loss—usually in one eye, and usually without warning.

Some early studies suggested a possible link between GLP-1 medications (particularly semaglutide) and NAION in the first 30 days of use. That understandably got a lot of attention.

But here's the fuller picture: when researchers compiled data across multiple controlled trials, the risk came out to approximately 0.04–0.09%. It’s not zero, but it’s very low, and actually lower than what was initially reported.

Certain factors can increase your individual risk:

• High blood pressure
• High cholesterol
• Diabetes
• A structural feature called a "disc at risk"—where the optic nerve is small and crowded, making it more vulnerable to changes in blood pressure

If you have a disc at risk, that's worth a conversation with both your eye doctor and prescribing physician before starting a GLP-1. For most people, though, this isn't a reason to avoid the medication.

GLP-1s and Diabetic Retinopathy

If you already have diabetic retinopathy (blood vessel changes in the back of the eye), starting a GLP-1 could temporarily make things look worse before they get better.

It's not unique to GLP-1s. Any treatment that drops your A1C quickly can trigger this response. The blood vessels in the retina can react to rapid glucose changes, and in some cases, they may start bleeding.

The good news: if your eye doctor knows your baseline, they can monitor for this and treat it early before it becomes a bigger problem. That's exactly why getting checked before you start treatment matters so much.

Why You Need a Baseline Eye Exam

Dr. Farahani is clear on this: everyone starting a GLP-1 should have had a dilated eye exam within the past year. For diabetic patients, that annual exam should already be happening, but it's worth confirming.

And when you go, ask specifically for a dilated exam. Some practices will offer photos as an alternative, but it's not the same thing. Photos can show a lot, but they don't give your doctor the full 3D view of your retina and optic nerve that a proper dilated exam does. Don't let them talk you out of it.

Symptoms That Should Never Wait

Most eye health monitoring can happen on a routine schedule, but some symptoms need same-day attention. Call your eye doctor immediately if you experience:

• Sudden painless vision loss in one eye
• A "blacked out" area in your visual field
• A shower of new floaters (small spots in your vision)
• Flashes of light that aren't really there
• A curtain-like shadow coming across your vision

No pain doesn't mean no problem. These symptoms can indicate serious issues—some treatable, some not—and waiting even a few days can make a difference in outcomes.

How to Protect Your Eyes Long Term

Beyond GLP-1s specifically, Dr. Farahani's advice for long-term eye health is straightforward:

• Wear sunglasses with full UVA and UVB protection. UV exposure accelerates cataract development and damages the macula over time.
• Get regular screening exams. Glaucoma is one of the most common causes of vision loss, and most people don't know they have it until significant damage has already been done. Early detection is key.
• Control what you can control. High blood pressure, high cholesterol, and uncontrolled diabetes are among the biggest threats to your eye health. Managing metabolic health is eye care.

On supplements: if you have macular degeneration, AREDS2 vitamins have solid evidence behind them and can reduce the risk of progression by around 20%. For everyone else, they're unlikely to make much difference, so Dr. Farahani advises to skip them and focus on the basics above.

GLP-1 medications are not the eye health threat the headlines make them out to be. The risks are real but small, and for most people, the benefits of better metabolic control far outweigh them.

What matters most is going in informed:

• Get a dilated eye exam before or shortly after starting treatment
• Know your personal risk factors
• Don't ignore symptoms, even if they're painless

As Dr. Farahani put it: "Tightening your glycemic control and getting metabolic syndrome under control is going to be the best thing for your eyes."

If you're worried about what GLP-1 medications might mean for your eye health, listen to the full episode with Dr. Mina Farahani.

TRANSCRIPT:

Disclaimer: The transcript below is provided for your convenience and may contain typos, errors, or grammatical inconsistencies, as it has not been professionally edited or proofread. Please enjoy it as-is and read at your own discretion.

Please note: The content shared in this podcast and blog post is for informational and educational purposes only and is not intended as medical advice. Always consult your healthcare provider for personalized medical guidance.    

 Welcome back to another episode of the podcast. I'm really excited. Today we have Dr. Mina Farahani, she is an ophthalmologist. I'm gonna let her introduce herself because she's even more specialized than that and give all the details. But the reason I brought her on today is because people have questions all day long about GLP ones and how does it affect eyesight and when is it good and when is it not?

Should I be. Doing things differently if I have different history. Before I have you introduce yourself though I always give a backstory as to why I bring someone on, because I'm not just like having random people on the podcast. We were in medical school together and do you remember we were out in like the boonies for one rotation we were at this townhouse together?

Yes. Because it was so far away from the city, Integra. Yes, yes. There was, I think there was like six of, you know, medical students in this house and I got to meet you there and I saw how you studied and I remember you were the first one where it was like, oh, you can lay the candle when you study.

It was just, you were so amazing. Was the candle, the quiet, relaxing music, the post-its all over my wall. Oh yeah, you saw, you got to know the real me. We go way back. Can you start out just introducing yourself a little bit and just so everyone knows a little bit more. Of course. So it's great to be here.

Thanks, Matea. My name is Mina Farhani. I'm a cornea cataract refractive specialist in private practice out in Southern New Hampshire at Spindel Eye. And I spend a lot of time talking with a lot of primary care providers about GLP ones and co-manage a lot of these patients. And so I know there's always a lot of questions that come up from.

Both patients and also the providers as well. So I'm really happy and excited to be on here and share things from the eye perspective with you guys. You know, most of the patients I see on these medications are on it because they need more control of their diabetes, their metabolic syndrome. We know that diabetes is one of the worst things for the eyes.

From my perspective, anything that can give us tighter glycemic control, lower all of those risk factors, cardiovascular factors, everything is ultimately going to be the best thing for the eyes. But there are some patients we have to watch a little bit closer. We do need some good baseline exams. And there's a few things you know, I wanna share in regards to that.

But ultimately, the take home point is. These medications. If GLP ones are going to lower your glucose, get your A1C down below seven, your eyes are going to be better off for it. What's the relationship with GLP ones and sudden vision loss? Can you just explain the nuance to us and what it actually is? Yeah, definitely. There's three different major risk factors I think about for GLP ones. Sudden vision loss is the one that we can see if a patient has something called the non arthritic ischemic optic neuropathy. Really long name, but N-A-I-O-N, basically it's an issue where the blood supply to the optic nerve, which is the nerve that connects to your eye, to your brain, gets diminished.

So you have this perfusion issue. It cuts off the blood supply to the nerve, and you can ultimately have painless vision loss related to that. Usually it's like the inferior portion of the vision just blacks out. There's no pain. It's usually just in one eye at a time, and the vision doesn't always come back.

Usually it doesn't always come back. A lot of times patients are lucky. Maybe it's just in the periphery, but it's still not a reversible process. There are some patients that just have an anatomic predisposition to developing this. There's something called a disc at risk if the shape of your optic nerve is really small and crowded.

Blood vessels can be twisty, turny there, and you can just, with a slight change in blood pressure too high or too low, you can get the blood pressure just cut off to your nerve and have this incidentally, which is very just an unfortunate anatomic thing. And then any, other risk factors are high blood pressure, so hypertension, hyperlipidemia, diabetes.

All things that affect the perfusion to your optic nerve can also increase your risk of having this problem. And then there were some studies, a few years back now that showed an increased risk of N-A-I-O-N for patients within the first month of starting GLP one. Agonist and so especially the risk was highest with semaglutide.

It was seen within the first 30 days, but you know, now they've done a lot of further analyses of all of these controlled trials and the jury's kind of out. There was one paper that said, yes, it's dangerous. Everyone should have baseline eye exam, check for discount risk, all the stuff. But then now when you're compiling some of the data, it's not quite as clear.

So the latest number I looked up to give it to you. They're saying it's about a 0.04 to 0.09% risk of having an N-A-I-I-O-N in that first month on a GLP one agonist medication. So that's really low. That's really, really low. And that's low so it's not zero, but it's. Point. Oh. I think that think, I think the first study had been like regular, well when I say regular population, people at risk, like 0.1% and then I think they had said 0.2, so this appears to be even lower then, is that It's even lower now.

Yeah, they've compiled all those studies, so it's super low. The thing that I would want to know, if I have a patient that's starting on it, do they have a disc at risk? Do they have a small crowded optic nerve, which isn't super common, but. It could just be an, an anatomic variant.

And for those patients, I'd have a, an in-depth discussion with them and talk with their primary saying, okay, they have this anatomic predisposition. Do you want to put them on something that could be another hit to their optic nerve? So for those patients, if there are some other medications that we could consider, maybe that would be a safer thing.

And so having a baseline eye exam is important. And generally the recommendation is for all of these patients going on a GLP one, make sure you've had a baseline eye exam within a year. And if it's a diabetic patient, they should be monitored at least once a year, just for screening eye exams. So most of those patients have had an exam.

But yeah, if you have a disc at risk, that's a different situation. But again, that's pretty rare. And when they're getting the eye exam, what do they specifically need to ask for? 'cause I mean there's like different levels when you get an eye exam, right? Sure. What do they need to ask so that they make sure that gets checked?

Yeah, you need a dilated eye exam. You may go to some practices and they'll say, oh, the pictures are just as good as a dilated eye exam. It's not the same. The pictures are great and we have the cameras in our offices and I love the pictures 'cause I could show patients. Most of what I could see, so with the photos, we can get pictures of your nerves.

It's not a 3D image. There's no depth to it, like I can see at the microscope with my lights and lenses, and so I can analyze your nerve better. I can check the peripheral retina, make sure there's no diabetic changes or bleeds or anything there. The photos will give us 80% of the picture, but.

It doesn't show me the whole retina, like a good dilated exam will. So definitely should have a full dilated exam for that baseline. So do you think that, I mean this is hard to say, but that anyone that would consider starting on a GLP one that, that it might be a best practice to get an eye exam first.

Definitely. Yeah, definitely. There's also studies for diabetic patients saying that, they do have a risk of if they have preexisting diabetic retinopathy, diabetic blood vessel changes in their eyes. They do have a risk of it getting worse within the first few months after starting treatment. You can see that in anyone who's having rapid lowering of their glucose.

So they've seen that in patients. To, certain intense insulin therapy regimen that, just a big drop in your A1C really quickly, whether you're getting there with GLP one or medication or insulin. If you're dropping it quickly, there's this point where the blood vessels in the back of the eye.

We don't really know why, but. They can react and start bleeding and your diabetes could get temporarily worse before it gets better. That's why we definitely want some baseline eye exam to know where you're starting is if it's a patient that already has a lot of changes, I may see them back a little sooner, maybe a month or two after they start therapy to make sure they don't get into a phase of active bleeding that requires treatment and things like that.

So baseline eye exam is really, really important. So I know how I need to monitor them. I've always thought, this is so cruel because the person's finally getting the blood sugar under control. And then it's like, surprise. I know, I know. Well, but the thing is, we can manage it, you know, if we're looking for it.

Yeah. And so a lot of these things can be really small, subtle findings that people may not notice that they have a few extra floaters. Well, that could be a bleed, you know? And that could be. Something that if it's not treated, can lead to vision loss. But you don't know until you get dilated and come in for an exam.

We'd like to pick things up and they're just starting so they don't lead to irreversible, issues. So eye exams are important. Yeah, so just to summarize. Probably great idea to get an eye exam before you start these medications. Yeah. What would be a reason for someone to get sooner follow up?

What type of eye symptoms versus just like, okay, this is routine, you go in once a year type of thing. Yeah, so painless vision loss. If you lose vision, if there's parts of vision missing, like blacked out areas, typically it would be very rare to get in both eyes at the same time.

But, typically one eye. Vision loss, never sit on that. Our practice, we see patients and we're on call 24 7, so we can always triage patients, get them in. That's really something you should not sit on call, and any eye doctor should be able to take you in for that type of urgent situation.

A whole bunch of new floaters would be concerning for a new bleed in the retina. So especially if it's a diabetic patient, a whole bunch of little spots showering down in your vision. And then, a retinal detachment, which would be less common. But with really bad diabetes changes, you can get the retina separating from the wall of the eye leading to a detachment, which could cause like a curtain coming over the vision and a lot of flashes of lights going off that aren't actually there.

So a whole bunch of floaters, a whole bunch of flashes, curtain, vision loss or parts of vision missing. They're pretty dramatic things, you know? And, and a lot of people say, well, there is no pain so I thought I could wait a few days. But the thing is, the diabetic things, there's a lot we can do.

There's treatments, there's, surgeries, there's in-office treatments, a bunch of things that can be done for the ischemic optic neuropathy, there's really no treatment for it. If you kind of hit the lottery in the wrong way, and develop that. We'll monitor and we'll make sure all of your risk factors are controlled and maybe, talk about medication changes or whatnot.

But, there's no actual treatment, for it at this time. Mm-hmm. It sounds occurring to me just in general. Do you have things that you recommend to patients that you think, help the eyesight long term? Whether it be like multivitamins, certain dietary things? Is there anything that you educate on with that?

There's some eye supplements for patients that have macular degeneration, that have certain types of macular degeneration, that have been shown to decrease the risk of going from dry. It was just like these little protein deposits in the back of the eye to the wet type that has bleeding or swelling.

And that's the type that can cause vision loss. So there's some eye vitamins. They'll all be called AREDS two A-R-E-D-S two 'cause that was the name of the study that showed they were effective and they decreased the risk. About 20% of going from that dry type to that wet type. That's one validated supplement.

That's great. But it's only shown to be effective in patients who already have macular degeneration if you're just taking it proactively. It's not really gonna do much. So in general, the best things you can do for your eyes are wearing sunglasses. UV light is bad for the macula, for cataract development, just full UB A and b protection.

And then avoiding things like hypertension, diabetes, hyperlipidemia, because you can get a lot of lasting, sequelae there. And then having screening eye exams, one of the most common. Causes a vision loss is glaucoma and glaucoma's a disease where the eye pressure is elevated, it causes optic nerve changes, and they can steal your peripheral vision over time.

Mm-hmm. A lot of people don't realize they have glaucoma until you've lost all the way and you're down to, affecting central vision. So something we can screen for. And if it's picked up early, we can start treatment with eye drops, laser treatments, different things to, decrease that progressive vision loss.

So screening eye exams can help pick that up, because it's something that you can have without even having any symptoms at all. Going in for just routine eye exams, wear sunglasses, and do everything you can to keep the rest of your body healthy. Yeah those really the best things you can do.

We can't do anything about genetics. And getting older, that's what I tell patients, it's out of our control. But, control what you can, and those are the things I'd recommend. Years ago I finally had prescription sunglasses made. It was like the best investment ever.

Yes, yes. Because I was like, why am I suffering with, like, trying to put the other ones on top or not having glasses on? Oh yes. It's a little luxury. Yep. Actually I was not gonna ask you about this, but I'm realizing it's related. Do you see any problems with people with the medication contra?

So will butrin, naltrexone, with elevated pressures in the eye or anything like that? No, there are some like Topamax that you can get issues with. Certain types of angle closure, glaucoma, very, very, very rare. It's like on our board exams, but, um, you know, very rare, we don't do any additional screening for those patients.

If they're having like an acute angle closure attack, they will come to us because they'll be in so much pain. That they will know they have to seek care. You know, that's kind of, they're in the emergency room or to us. So no, no extra screening needed. So for anyone who's listening, the Topamax, that's gonna be with Phentermine, that's gonna be qia.

So just like in the sort of weight management space, if anyone's listening,

do you think that there's anything else in this topic that's important for people to hear about? I think I wanna emphasize, there. Ultimately, if you are getting your glucose under control, whatever it takes, GLP ones are very safe, these risks are all very low, but these are things that we can monitor you for.

Make sure you get in with your friendly neighborhood ophthalmologists. Make sure you get dilated. Don't get talked into the photos. These are things that we can watch you for and make sure you don't get into any trouble for it. But ultimately. Tightening your glycemic control, getting metabolic syndrome under control is gonna be the best thing for your eyes.

It's great that we have more options now than we did before. Thank you for answering all these questions. I think people are just gonna now be able to get the most up-to-date data on this and just maybe be able to feel a little bit better about it because I think it's really, it's blown to be bigger proportion online and the reality is, like you were saying, if you have uncontrolled blood pressure and diabetes and things like that, I think that.

Poses a higher risk than, the risk with a GLP one medication. And of course, everyone's gonna talk to their physician. Is there a good way that if people want to, find out more about how to either see you in clinic or online, things like that, are there a good methods to follow you?

Yeah, definitely. You can check out my Instagram. It's Mina, M-I-N-A-F-A-R-A-H-M-D. And our website is spindel i dot com. I'm happy to help out if there's any questions that come up. Happy to be a resource.

Awesome. Thank you so much. If anyone's listening, we'll have all of this listed on renta clinic.com.

If you click on podcast you click on this episode. We have everything written out, everything linked. Thank you so much for coming on today. Thank you. It's a great discussion.

Thanks for having me,Matthea